28 August 2015

Self-healing material could patch up damaged spacecraft in under a second

Space is big and mostly empty, but it’s the small part that isn’t empty that ends up being an issue for space exploration. Even a tiny piece of debris from a derelict satellite or ancient bit of space rock can cause damage to a spacecraft, and that damage can expose your fragile atmosphere-loving body to the harsh vacuum of space in a real hurry. Researchers from the University of Michigan working with NASA have developed a material that might add an extra layer of protection from space debris, a material that can heal itself to seal hull breaches.

The International Space Station is the most heavily shielded craft ever built, a necessary distinction as it’s designed to operate for years in orbit. The current design relies on a series of impact shields known as Whipple bumpers or Whipple shields. These bumpers are essentially thin layers of material that stand off from the hull of the station by at least several centimeters. When a small object impacts the station, the impact with the Whipple bumper slows it down and may even cause it to break up. The result is a lower force spread over a larger surface area of the actual hull.

If the bumpers were to fail, the station would have a weak spot that could lead to a hull rupture. The work by U of M scientists might offer an added layer of protection. This new material is composed of a type of liquid resin called thiol-ene-trialkylborane. It’s sandwiched between two polymer panels to form an airtight seal. The resin remains liquid as long as that seal remains unbroken. Should a projectile pierce the hull of a ship that includes this material, it will no longer be sealed. The resin leaks out through the breach, and that’s when the magic (science) happens.

On one side of the breach is vacuum, but as we’ve all learned from TV and movies, the air inside a spacecraft will be sucked out quickly. The air on the inside of the ship reacts with the resin as it leaks out, causing it to harden into a solid plug that stops more atmosphere from escaping. This happens extremely fast as well the video above shows the resin hardening in just a few milliseconds.

The plug only has to hold one atmosphere of pressure inside the ship, so it doesn’t have to be as strong as the undamaged hull. It just needs to be good enough to keep everyone alive while they make proper repairs. While space is the main application, the researchers also say it could be useful in automotive and building technology.